1.0 Field of the Invention
The present invention relates generally to ceiling fans and, more particularly, to ceiling fans having the blade irons which support the fan blades mounted to a rotatable fan housing.
2.0 Related Art
Ceiling fans include a plurality of fan blades which are rotated by an electric motor to provide a supplementary means of conditioning air within both commercial and residential buildings. Ceiling fans typically include a stationary fan housing, which may include an ornamental exterior design and may assume a wide variety of shapes, disposed in surrounding relationship with the electric motor. Fan housings are sometimes referred to in the art as motor housings. However, it is understood in the art that the primary purpose of fan housings is to obscure the electric motor from view to provide a more aesthetically pleasing appearance to the ceiling fan and it is further understood that the fan housing is not part of the electric motor but instead is a separate component of the ceiling fan. The stationary fan housing is supported by the stationary structure used to suspend the ceiling fan. For instance, with ceiling fans utilizing a downrod and ball arrangement in conjunction with a ceiling mounted canopy to suspend the fan, the stationary fan housing may be attached to an adaptor which is secured to the lower end of the downrod.
The electric motors used in ceiling fans comprise either xe2x80x9cstandard configurationxe2x80x9d or xe2x80x9cinside-outxe2x80x9d electric motors. With xe2x80x9cstandard configurationxe2x80x9d motors the rotor, which comprises a rotating portion of the motor, is disposed radially inwardly of the stator or stationary portion of the motor which includes the electric windings of the motor. The opposite configuration exists in xe2x80x9cinside-outxe2x80x9d motors, i.e., the rotor is disposed radially outwardly of the stator. Regardless of the type of electric motor used, it may be appreciated that the fan blades must be connected to and rotatably driven by a rotating portion of the motor to provide the desired rotation of the blades. The rotating portion of an xe2x80x9cinside-outxe2x80x9d electric motor may include upper and lower end caps or end bells in addition to the rotor.
Various means may be used to mount the fan blades to the rotating portion of an xe2x80x9cinside-outxe2x80x9d electric motor of a ceiling fan, with one commonly employed mounting arrangement being disclosed in U.S. Pat. No. 5,462,412. As best seen in FIG. 2, each fan blade 20 is fastened to a distal end 66 of a blade iron 62, with the proximal end 64 of each blade iron 62 being fastened to a lower surface 72 of motor 16 via screw 70.
Another commonly employed ceiling fan blade mounting arrangement is disclosed in U.S. Pat. No. 5,222,864. As shown in FIGS. 2 and 3, the radially inner end of each fan blade 20 is mounted to a wedge shaped member 84 disposed on an upper surface 22 of motor 16 via screws 88. It is noted that the fan housings disclosed in each of the foregoing patents (denoted by reference no. 18 in both patents) comprise stationary housings.
U.S. Pat. No. 5,944,487 discloses yet another ceiling fan blade attachment system. As shown in FIG. 1, the disclosed system includes a blade mounting ring 21 which is disposed below and fixedly attached to a motor mounting face 5 of a rotatable, lower motor casing portion 13 of inside-out motor 1 via bolts 17. The blade mounting ring 21 includes a plurality of fan blade mounting brackets 31 which extend outwardly from a substantially cylindrical portion 29 of ring 21. Each of the disclosed fan blades 35 is affixed to the underside of one of the brackets 31 with screws or bolts.
U.S. Design Pat. No. D.361,377 discloses two embodiments of a ceiling fan and light fixture which include a fan housing having stationary upper and lower portions and a rotatable center portion disposed therebetween, with each fan blade passing through slots formed in the center portion of the fan housing at a location near the inner end of the blade. Although not shown in the design patent, it is known in the art that the rotatable center portion of the fan housing is mounted to a rotatable lower portion of the included electric motor. As further known in the art, the radially inner end of each fan blade is attached to a radially outer portion of a blade iron which is attached, at a radially inner end thereof, to the rotatable lower portion of the electric motor.
Known ceiling fans also include those having a rotatable fan housing with a lower portion of the fan housing secured to the lower, rotatable end cap of the electric motor, with these fans further including blade irons attached to a bottom, downwardly facing surface of the lower portion of the fan housing.
With regard to xe2x80x9cstandard configurationxe2x80x9d electric motors, the fan blades may be attached to blade irons which are in turn are attached to a rotating flywheel which is secured to a rotor shaft of the electric motor.
Although each of the foregoing fan blade mounting arrangements have enjoyed widespread use, ceiling fan designers continue to search for alternative fan blade mounting arrangements which provide a different xe2x80x9clookxe2x80x9d to the ceiling fan and which may provide various advantages associated with the manufacture, shipment, assembly and operation of the ceiling fan.
In view of the foregoing needs, the present invention is directed to a ceiling fan having a different look which is aesthetically pleasing, and several functional advantages, due to the incorporation of side mounted blade irons. More particularly, the ceiling fan of the present invention includes blade irons which are mounted to a radially outwardly facing surface of a rotatable fan housing, with each fan blade being attached to one of the blade irons. In a preferred embodiment, this surface is an outer surface of a substantially cylindrical sidewall of the housing. Since the blade irons are mounted directly to a side surface of the rotatable motor housing, the blade irons may be smaller than those often used with conventional ceiling fans which are mounted to a bottom portion of the motor and are xe2x80x9cloopedxe2x80x9d to obtain the desired vertical position of the blade iron. Accordingly, the blade irons incorporated by the ceiling fans of the present invention may be cheaper, lighter and have a longer service life due to reduced chance of fatigue, as compared to blade irons typically used with conventional ceiling fans. Further, the mounting position of the blade irons will result in less imbalance and therefore reduced xe2x80x9cwobblexe2x80x9d during operation of the ceiling fan due to a reduction in manufacturing variations in radial location of the bolt holes used to attach the fan blades to the blade irons. The expected reduction in operational ceiling fan wobble is also due to a variety of additional factors including the following. In the first instance, it is believed that the geometry of the blade irons, which extend radially outwardly from the base attached to the substantially cylindrical sidewall of the rotatable housing, will permit less variation in blade center of gravity and blade pitch angle as compared to ceiling fans incorporating blade irons having more complex geometries, such as the aforementioned xe2x80x9cloopxe2x80x9d due to attachment to the bottom portion of the motor. As known in the art, variations in blade pitch angle contribute to ceiling fan wobble. Furthermore, the simplified geometry of the blade irons results in substantially radially directed forces, as compared to the complex force vector of conventional blade irons having more complex geometry, which enhances the chance for improved fan balancing and therefore reduces operational wobble. Yet another advantage associated with the ceiling fan of the present invention is associated with the shipment of the fan from the manufacturer""s facility. The attachment of the rotatable motor housing to the rotor, via multiple circumferentially spaced fasteners, provides a more rigid structure than that associated with many conventional ceiling fans employing a stationary motor housing attached to a centrally disposed adaptor connected to the stator shaft of the motor. Accordingly, the package used to ship the ceiling fan of the present invention may be simplified relative to that employed with many conventional ceiling fans. The blade mounting arrangement included in the ceiling fan according to the present invention also provides a simple installation of the blade irons, used to support the fan blades, for the end consumer which is considered to be easier than that associated with typical fan blade mounting arrangements of conventional ceiling fans. For instance, with conventional ceiling fans, it is often necessary for the consumer to remove at least a top cover of the ceiling fan switch housing to gain access to the motor surface to which the blade irons are attached.
According to one preferred embodiment the present invention is directed to a ceiling fan comprising a means for suspending the ceiling fan from the ceiling of a structure and an electric motor having a rotating portion and a stator. The rotating portion of the electric motor includes a rotor, an upper end cap and a lower end cap, with the upper and lower end caps being attached to the rotor. The stator includes a stator shaft connected to the means for suspending the ceiling fan. The means for suspending the ceiling fan may include a hollow canopy which includes a seat and may be mounted to the ceiling of the structure via a bracket, a downrod, an adaptor secured to a lower end of the downrod, and a ball secured to an upper end of the downrod and disposed within the seat of the canopy. The adaptor may include a radially extending flange portion and upper and lower substantially cylindrical portions, with the upper substantially cylindrical portion being secured to the downrod and the lower substantially cylindrical portion of the adaptor being secured to the stator shaft.
The electric motor may comprise an inside-out electric motor wherein the rotor of rotating portion of the motor is disposed radially outwardly of the stator. However, in other embodiments, the motor may comprise a standard configuration electric motor, i.e., one in which the rotor is disposed radially inwardly of the stator.
The ceiling fan further comprises a rotatable fan housing disposed in surrounding relationship with the electric motor, with the rotatable fan housing being attached to the rotating portion of the electric motor. In one preferred embodiment, the rotatable fan housing is attached to a bottom surface of the lower end cap of the rotating portion of the motor. The ceiling fan may include a plurality of resilient grommets, each having an upper portion disposed between the electric motor and the rotatable fan housing, which act as vibration isolators or dampeners. The rotatable fan housing includes a radially outwardly facing surface which may have a substantially cylindrical shape.
The ceiling fan further includes a plurality of blade irons, and a like number of fan blades, with each of the blade irons being mounted to and protruding outwardly from the radially outwardly facing surface of the rotatable fan housing. Each of the fan blades includes a radially outer and a radially inner end, with the radially inner end being supported by one of the blade irons. Each of the blade irons include a circumferentially extending base, which is mounted to the radially outwardly facing surface of the rotatable fan housing, and a radially outwardly extending blade supporting portion. Each blade iron may also include a connecting portion interconnecting the base and blade supporting portion. The base, blade supporting portion and connecting portion are preferably made as an integral casting. The blade supporting portion may include a plurality of internally threaded bosses for the purpose of fastening the radially inner ends of the blades to the blade supporting portions of the blade irons.
The ceiling fan may further include a stationary fan housing which is attached to the means for suspending the ceiling fan. In one embodiment, the stationary fan housing is attached to the radially extending flange portion of the adaptor included in the means for suspending the ceiling fan.